1. Field of the Invention
The present invention relates generally to dissolution test equipment, and more particularly, to the washing of dissolution vessels that are used in a dissolution testing system.
2. Description of the Related Art
Drug dissolution, i.e., the rate of drug release from bulk powder or a finished drug product into the human body, is becoming an increasingly important aspect of the biopharmaceutical equation, particularly with the advent of controlled-release dosage forms and the increasing use of poorly-soluble and water-insoluble drugs. Through the use of experimentally-determined drug and drug product in-vitro characteristics, such as solubility and dissolution, it is possible to predict the in-vivo performance for certain classes of drugs. Scientists in the pharmaceutical and nutritional industries use dissolution testing equipment to determine bioavailability, i.e., the rate at which active ingredients in drug forms become available to be used by the body. Bioavailability testing by this method is required throughout the pharmaceutical manufacturing process to ensure product quality and stability. Other, non-pharmaceutical applications for dissolution testing exist, as well.
Dissolution testing is typically performed using test equipment that holds a plurality of vessels and submerges the vessels in a temperature-controlled dissolution bath. Each vessel is then filled with a dissolution medium in which a solute is placed, e.g., in a mesh basket. The dissolution medium is then stirred using a stirring element, e.g., a rotating paddle. The stirring elements and baskets corresponding to each of the vessels are typically collectively mounted on a single drive head, so that they can be raised or lowered in unison. At some point, one or more samples of the resulting solution are taken from the vessel and evaluated, e.g., using a spectrophotometer, either in situ or by transporting the samples to an external device. Once testing is complete, the vessels are usually transported to a sink or other station for cleaning, which involves draining, washing, and sometimes drying the vessels. Once cleaning is complete, and prior to re-use of the vessels for subsequent testing, the precise location and centering of each vessel and the height adjustment of the stirring element must be verified. Each time a vessel is replaced after cleaning, this verification process needs to be repeated to maintain consistent and accurate parameters. Depending on the number of vessels, the cleaning and verification processes can be tedious, time-consuming, and inefficient.